1. Technical Field
The present invention relates to stencils, and particularly to a legend printing stencil and a method for manufacturing printed circuit boards using the legend printing stencil.
2. Description of Related Art
Printed circuit boards are widely used in electronic products for electrical connection. Printed circuit boards are usually manufactured in a series of processes including drilling holes, facturing electrical traces, printing solder resist, printing legends, electroplating gold and inspecting. Generally, printing legend refers to apply identification nomenclatures (e.g., legends, logos or serialization numbers) to prototypes of printed circuit boards using a legend ink material. Typically, identification nomenclatures are added to prototypes of printed circuit boards using a stencil printing technology.
Correspondingly, a typical large stencil of printing legends having a number of printing portions corresponding to a number of printed circuit boards is used to print legends on the printed circuit boards simultaneously. However, in a process of printing legends, a squeegee only can squeegee one of printing portions to print one of printed circuit boards once. Repeated squeegeeing may cause overlap of the legend ink material at a connection portion of two neighboring printing portions, thereby affecting quality of printing legends.
Additionally, during manufacturing printed circuit boards, a connection portion of two neighboring printed circuit boards has a copper layer thereon. The copper layer is not formed into electrical traces and has no solder resist formed thereon. In an electroplating process, a gold layer may be deposited onto the copper layer of the connection portion. However, the connection portion is generally abandoned after separations of the printed circuit boards. As a result of that, the gold layer deposited on the copper layer of the connection portion becomes waste. If the copper layer of the connection portion is removed before electroplating, the mechanical property and flexibility of the large substrate may be lowered/deteriorated. As such, the manufacturing of a number of printed circuit boards cannot be performed properly, especially using the roll-to-roll process.
What is needed, therefore, is a legend printing stencil that is suitable for manufacturing a number of printed circuit boards, and a method for manufacturing printed circuit boards using the legend printing stencil.